Conventional toothbrushes, in which brush staples are floatingly movable with respect to brush base portion, are described in, for example, Publication Gazette of Japanese Patent Application 5-123218 shown in FIG. 13 and Publication Gazette of Japanese Patent Application 7-265127 shown in FIG. 14. In the conventional toothbrushes which are not the power toothbrush, a brush base portion 2′ is formed in the vicinity of a top end opposite to a grip portion of a main body the toothbrush. A plurality of floating bases 3 is floatingly provided in the brush base portion 2′, and a blush staple 4 is planted on each floating base 3.
In the conventional toothbrush, the brush staples 4 are floatingly movable with respect to the brush base portion 2′, so that top ends 4a of the brush staples 4 can be contacted along convex and concave shapes of human teeth (not shown in the figure). Thus, dirt on the teeth such as plaque and so on can be removed while the teeth are polished.
In the conventional toothbrush in which the brush staples 4 are floatingly movable with respect to the brush base portion 2′, the brush base portion 2′, however, is integrally formed with the grip portion as the main body of the toothbrush. It is necessary to move the main body of the toothbrush reciprocally or rollingly by human hand for removing the dirt of the tooth. In such the case, the top ends 4a of the brush staples 4 can be contacted along the convex and concave shapes of the human teeth. Stroke and frequency of the reciprocal motion or the rolling motion of the toothbrush, however, become uneven. When the brush staples 4 are moved in the interdental portion of the teeth where much dirt is remained, it is necessary to move the brush staples 4 largely. Thus, the brush staples 4 occasionally polish another teeth faces when the brush staples 4 move over the interdental portion of the teeth, or a part of the brush staple 4 occasionally is hooked on the interdental portion of the teeth. As a result, the conventional toothbrush cannot remove the dirt in the interdental portion of the teeth effectively.